30 January 2023 - Matthew Oakley

Featured in: Market Insights, Intrusion detection

Within the security industry, false alarms are the bane of any good installer so it is understandable that whenever they are proposing a new installation it is always in the back of their mind. Not only do false alarms infuriate customers, but they also have a strong impact to costs and additional workload for installers.

Experience has demonstrated that relying on one single technology often doesn’t work to deliver a complete security solution including detection, surveillance and categorisation. Detection technologies will perform reliably by detecting movement, but they can’t categorise the objects detected. On the other hand, video analytics will allow to categorise, but their ability to accurately detect trigger events will be affected by lighting or weather conditions, which can lead to excessive number of nuisance alarms.

Sensors and camera complete system

Benefits of Sensors

Sensor-led solutions benefit the security system by significantly reducing false and nuisance alarms, particularly when deploying outdoor security systems.

A major benefit of detectors is that they do not require additional lighting infrastructure to work, they can work in perfect darkness or where triggering an external light is not appropriate or possible (for instance in residential areas, high-security sites where discretion is required, metro tunnels, etc).

Another major benefit to using sensor detection technology is that it can function in changing environmental conditions. Depending upon the detector used, they have different types of environmental algorithms on board to make them stable, no matter the weather conditions, meaning they can adapt to their environment to make sure they are always detecting accurately.

Cameras can often be triggered by rain, snow, blowing leaves in windy conditions and more which creates costly nuisance alarms. By adding a layer of detection you can avoid this and create an intelligent security system that can be relied upon. Our PIR detection sensors are equipped with digital logic such as our unique SMDA (Super Multi-Dimensional Analysis) which allows the detector to analyse the passive infrared signals and environmental information so it can distinguish between genuine intrusions and nuisance alarms due to changes in temperature or other conditions. An example of how this works can be seen in our pet tolerant sensors, where the digital logic allows the sensor to better analyse the passive infrared signals and not recognise small pets, lowering false alarms.


With correct set up and commissioning, the detectors will reliably detect and activate an alarm accurately at their furthest possible distance and close up to the detector head. Detectors which have been asked to trigger on a particular mass size, will calibrate themselves and work out how far away the moving target is, so that it will always create an accurate alarm.

Combining Detection and Surveillance

The obvious positive of a video system is that security teams can visually see what has created the event, provided it occurs within the field of view of the camera. As an image is being captured by a camera, it can classify what the moving object is, if this falls within its threat parameters it will trigger an event.

By combining both technologies, the system can benefit of reliable detection and vision to give the security teams a more reliable and complete understanding of the situation.

A high false alarm rate can be caused through insects crawling across the field of view of a camera. Due to the close-up nature of the insect across the camera glass, it can create a large pixelation change, in turn resulting in a false trigger of the system. 18% of false alarms in 2021 were as a consequence of cobwebs on cameras. Having sensors integrated into your CCTV will prevent this nuisance alarm from occurring.


Not every sensor will suit every application, which is why at OPTEX we have such a large portfolio of detection products and technologies, to suit different types of sites, needs and security levels. Our intrusion detection technologies work either by receiving infrared energy, infrared light being broken, lasers using time of flight or light passed through a fibre optic cable activating on vibrations. What all these sensing technologies have in common is they have been specifically developed to ‘detect’. We advocate a multi-layered approach as the most reliable and effective way to detect an intrusion, minimising risks by combining different technologies to create layers of defence that can detect early intrusions and deter them as much as possible; after all sticks in a bundle are unbreakable.

Find out more about our multi-layered solutions

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